Self-study
Support A large group of hyperactive children whose regular diets included food containing large amounts of additives was observed by researchers trained to assess the presence or absence of behavior problems. ███ ████████ ████ ████ ██████ ██ █ ████████████ ████ ███ ███████ ██████ █████ █████ ████ ████ ████████ ██████ ██████████ ██████ ██ ███████ ██ ███ ████████ █████████ ████████ █████████ █████ ███ ██████ ██ █████ ████ ██ ███████ ███ ███ ██ ███ █████ ██ █████ █████ ██ ███ ██ █████████ ████ ████ █████████ ███ ██████████ ██ ████████ ████████ ██ ███████████ █████████
Argument Summary
The phenomenon: Researchers observed a group of hyperactive children whose diets included lots of food additives. Nearly 60% of the children had behavior problems. After the children were switched to a low-additive diet for several weeks, only 30% had behavior problems.
The hypothesis: The author concludes that food additives can contribute to behavior problems in hyperactive children. In other words, the author thinks the reduction in additives is what caused the improvement in behavior.
Anticipation
The author observes a correlation between reducing food additives and a reduction in behavior problems, and concludes that food additives contributed to the behavior problems. But does a drop from 60% to 30% after a diet change prove that the additives were the cause?
Not necessarily. Maybe the change in behavior had nothing to do with the additives at all. Perhaps the children's behavior improved simply because several weeks had passed, or because the researchers' increased attention made the children behave better, or because of some other factor that coincided with the diet change. The study doesn't have a control group—a comparable group of children who didn't change their diet—so we can't rule out the possibility that the same improvement would have occurred without the diet change.
10.
The evidence cited fails to █████████ ███ ██████████ ███████
a
there is no ████████ ████ ███ █████████ ██ ████████ ████████ ███ █████████████ ██ ███ █████████ ██ █████████████ ██████
The conclusion is that food additives can contribute to behavior problems. This is a modest claim—it just says additives play some role. It doesn't claim that the relationship between additives and behavior problems is perfectly linear. So we don't need evidence that the reduction in behavior problems was proportionate to the reduction in additive intake.
Think about it this way. Suppose we learned that the children's additive intake was cut by 80%, but behavior problems only dropped by 50%. That's not proportionate, but it would still be consistent with additives contributing to behavior problems. Maybe additives are just one of several contributing factors, so reducing them helps but doesn't produce a perfectly matching reduction in behavior problems. The lack of a proportionate relationship wouldn't undermine the conclusion. The real problem with the argument is that the study lacks a control group, so we can't tell whether the additives had any effect at all.
b
there is no ███ ██ ████ ████ ███████ █████ ████ ████████ ███████ ███ ██████ ██ █████ █████ ████ ████████ ███ ███████ ██ █ ████████████ ████ ████ ███████
This identifies the key flaw. The study only looked at children who switched to a low-additive diet. There was no control group—no comparable group of children who kept eating the same diet. Without that comparison, we can't know whether the improvement in behavior was caused by the diet change or by something else entirely. Maybe the children's behavior would have improved over those several weeks regardless of what they ate. The study's design doesn't allow us to isolate the effect of the additives, which means the data don't establish that food additives contributed to the behavior problems.
c
exactly how many ████████ █████████ ████████ ████████ █████ ███ ██████ ██ ████ ██████ ██ ███████████ █████ ███ ████ ██ ███ █████ ███████ ██ ███ █████████ █████
Not knowing the exact size of the group doesn't undermine the conclusion. Percentages are enough to establish a meaningful comparison between the before and after observations. Whether the group had 50 children or 500 children, the drop from 60% to 30% represents the same proportional change. The issue with the argument isn't about how precise the numbers are.
d
there is no ████████ ████ ███ ████████ ██ ████ ██ ███ ████████ ███ ██████████ ██ █████████
The conclusion claims that additives can contribute to behavior problems, not that additives affect every child. So the fact that some children's behavior might be unaffected by additives is perfectly consistent with the conclusion. The argument doesn't need to show that additives affect all children in order to conclude that additives can contribute to behavior problems in some children.
e
the evidence is ██████████ ████ ███ █████ ████ ████ ████████ ███████ ████ ████████ ████████ ████████ █████ █████ ██ ███ ████████████ ████ ████ ████ ███ █████████ ████ █████ ████████
Even if some individual children got worse after the diet change, the overall data still show a drop from 60% to 30%. The conclusion is about whether additives can contribute to behavior problems generally, not about what happened to every individual child. The fact that some children might not fit the trend doesn't undermine the overall pattern. The real problem is that we don't know whether the overall pattern was caused by the diet change in the first place.